Hi,
I have some images with wrong metadata. They are tagged as pixel-is-area images
and listgeo shows the tag
GTRasterTypeGeoKey (Short,1): RasterPixelIsArea
Actually geotiffs are measurements and they should use RasterPixelIsPoint and
images should be shifted be half a pixel on a map.
I was thinking that I can make a clever fix with gdal_edit so I made a copy of
"area.tif" as "point.tif" and then I edited it
gdal_edit -mo AREA_OR_POINT=Point point.tif
The key gets edited into RasterPixelIsPoint just as I wished. However, the
georeferencing that is stored into tag 33922 gets edited by the same.
Before edit:
ModelTiepointTag (2,3):
0 0 0
115 33 0
ModelPixelScaleTag (1,3):
0.1 0.1 0
After edit:
Tagged_Information:
ModelTiepointTag (2,3):
0 0 0
115.05 32.95 0
ModelPixelScaleTag (1,3):
0.1 0.1 0
Because the ModelTiepoint gets shifted by half a pixel it compensates the shift
caused by image-is-area vs. image-is-point and the image footprint and pixels
stay exactly where they used to be. I know I can use gdal_edit again with
-a_ullr ulx uly lrx lry for shifting the image but I wonder if there happens to
be some trick for just changing raster type into pixel-is-point without
touching the tiepoint. Option "swap PixelIsPoint/Area" in gdal_edit would be
fine for me if the current behavior with -mo AREA_OR_POINT=Point feels correct.
-Jukka Rahkonen-
_______________________________________________
gdal-dev mailing list
[email protected]
https://lists.osgeo.org/mailman/listinfo/gdal-dev
